.welcome-message {
    font-weight: bolder;
    font-size: 1.5em;
    color: #333;
    font-family: 'Arial', sans-serif;
    }
  a{
      text-decoration: none;
      display: block;
      color: inherit;
  }
  .navbar {
      display: flex;
      justify-content: space-between;
      align-items: center;
      background-color: #f5fcff;
      padding: 10px 20px;
      position: relative;
  }
  .navbar-left,
  .navbar-right {
      display: flex;
      align-items: center;
  }
  .navbar-center {
      display: flex;
      align-items: center;
  }
  .navbar a {
      text-decoration: none;
      color: black;
      padding: 10px 15px;
      margin: 0 5px;
      transition: color 0.3s, background-color 0.3s, border-radius 0.3s;
  }
  .navbar a:hover {
      color: white;
      background-color: #007bff;
      border-radius: 15px;
  }
  .dropdown {
      position: relative;
  }
  .dropdown-content {
      margin-top: 20px;
      display: none;
      position: absolute;
      background-color: #fff;
      border: 1px solid #007bff;
      border-radius: 15px;
      padding: 10px;
      box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
      z-index: 1;
      top: 100%;
      left: 50%;
      transform: translateX(-50%);
      white-space: nowrap;
      opacity: 0;
      transition: opacity 0.5s ease, visibility 0.5s ease;
      visibility: hidden;
  }
  .dropdown-content a {
      color: black;
      padding: 10px 15px;
      text-decoration: none;
      display: flex;
      align-items: center;
  }
  .dropdown-content a i {
      margin-right: 5px;
  }
  .dropdown:hover .dropdown-content {
      display: flex;
      opacity: 1;
      visibility: visible;
  }
  .dropdown:hover .dropbtn {
      color: white;
      background-color: #007bff;
      border-radius: 15px;
  }
  .dropbtn{
      font-family: 'Microsoft YaHei', 'SimSun', sans-serif;
      font-weight: bold;
      letter-spacing: 5px;
  }
  .container {
      display: flex;
      justify-content: space-between;
      padding: 20px;
      max-width: 1200px;
      margin: auto;
      position: relative;
  }

  .box {
      height: 330px;
      width: 550px; /* 确保第一个 box 的宽度是 550px */
      background-color: white;
      border-radius: 10px;
      box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
      overflow: hidden;
      flex: 1;
      margin: 10px;
      background-size: cover;
      background-position: center;
      background-repeat: no-repeat;
      position: relative;
  }

  .box .content {
      padding: 20px;
  }

  .box .content h1 {
      font-size: 24px;
      margin: 0 0 10px;
      color: white;
  }

  .box .content p {
      margin: 0;
      color: white;
  }

  .buttons {
      display: flex;
      justify-content: center;
      margin-top: 20px;
  }

  .buttons a {
      text-decoration: none;
      color: white;
      background-color: #007BFF;
      padding: 10px 20px;
      border-radius: 5px;
      margin: 0 10px;
      transition: background-color 0.3s;
  }

  .buttons a:hover {
      background-color: #0056b3;
  }

  .small-boxes {
    display: flex;
    flex-direction: row;
    align-items: flex-end;
    position: relative;
    bottom: -30px;
    left: -20px;
    width: 550px; /* 确保小方框总宽度与第一个 box 的宽度一致 */
    height: 50px;
}

.small-boxes a {
    display: flex;
    flex: 1;
    text-decoration: none;
    margin: 0;
    transition: flex 0.3s ease; /* 添加过渡效果 */
}

.small-boxes a:hover {
    flex: 2; /* 鼠标悬停时，增加该链接的宽度 */
}

.small-box {
    height: 70px;
    flex: 1;
    border-radius: 10px; /* 设置圆角 */
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
    background-size: 300% 300%; /* 设置背景大小 */
    margin: 10px;
    display: flex;
    align-items: center;
    justify-content: left;
    padding-left: 10px;
    color: white;
    font-size: 16px;
    font-weight: bold;
    position: relative;
}

/* 第一个 box 的动画 */
#box1 {
    background: linear-gradient(135deg, #87CEEB, #B0E0E6, #6A5ACD);
    background-size: 300% 300%;
    animation: gradient1 15s ease infinite;
}

@keyframes gradient1 {
    0% {
        background-position: 0% 50%;
    }
    50% {
        background-position: 100% 50%;
    }
    100% {
        background-position: 0% 50%;
    }
}

/* 第二个 box 的动画 */
#box2 {
    background: linear-gradient(135deg, #FF7F50, #FFA07A, #FF6347);
    background-size: 300% 300%;
    animation: gradient2 15s ease infinite;
}

@keyframes gradient2 {
    0% {
        background-position: 0% 50%;
    }
    50% {
        background-position: 100% 50%;
    }
    100% {
        background-position: 0% 50%;
    }
}

/* 第三个 box 的动画 */
#box3 {
    background: linear-gradient(135deg, #228B22, #6B8E23, #FFD700);
    background-size: 300% 300%;
    animation: gradient3 15s ease infinite;
}

@keyframes gradient3 {
    0% {
        background-position: 0% 50%;
    }
    50% {
        background-position: 100% 50%;
    }
    100% {
        background-position: 0% 50%;
    }
}
  .navbar.night-mode {
      background-color: #1f1f1f;
  }
  .navbar a.night-mode {
      color: white;
  }
  .navbar a.night-mode:hover {
      background-color: #555;
  }
  .dropdown-content.night-mode {
      background-color: #2c2c2c;
      color: white;
  }
  .dropdown-content a.night-mode {
      color: white;
  }
  .box.night-mode {
      background-color: #1f1f1f;
  }
  .buttons a.night-mode {
      background-color: #555;
  }
  .buttons a.night-mode:hover {
      background-color: #333;
  }
  .announcement.night-mode{
      background-color: #1f1f1f;
  }
  .announcement_content.night-mode{
      color: white;
  }
  .announcement {
      width: 80%;
      margin: 0 auto;
      overflow: hidden;
      background-color: white;
      color: #333;
      font-size: 18px;
      padding: 10px;
      box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
      position: relative;
      height: 30px;
      display: flex;
      align-items: center;
      border-radius: 15px;
  }
  #announcement_icon {
      margin-right: 10px;
      font-size: 24px;
      color: #0e0e0e;
  }

  .announcement_content {
      position: absolute;
      top: 0;
      left: 0;
      right: 0;
      bottom: 0;
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      animation: scroll 10s infinite;
      opacity: 0;
      transition: opacity 0.5s ease-in-out;
  }
  .announcement-content-container {
      position: relative;
      width: calc(100% - 34px); /* 调整宽度以适应图标 */
      height: 100%;
  }
  #announcement_icon.night-mode {
      color: white;
  }

  @keyframes scroll {
      0% {
          opacity: 0;
          transform: translateY(100%);
      }
      10% {
          opacity: 1;
          transform: translateY(0);
      }
      40% {
          opacity: 1;
          transform: translateY(0);
      }
      50% {
          opacity: 0;
          transform: translateY(-100%);
      }
      100% {
          opacity: 0;
          transform: translateY(-100%);
      }
  }